Locking arrangement for a container with a cap

ABSTRACT

The present invention relates to a locking arrangement for detachably locking a cap having a skirt on a container having an enclosure opening into an opening. The cap includes a number of keys spaced along the inside of the skirt of the cap and a number of projections spaced along the outside of the enclosure of the container in an area having a mainly circular cross section and defining an axis. The locking arrangement also includes a slot made in each projection and having a base at the opening of the container and the opposite inlet for insertion of a key. Cooperative contact faces are made on the skirt and enclosure respectively and seen in cross section, they form an angle with each other. The contact faces of the cap are made on the inside of the skirt and/or the free ends of the keys and the contact faces of the container are made on the projections and/or the enclosure at a greater distance from the axis than the contact faces of the cap. Thereby a locking arrangement is obtained that is easy to operate and continuously maintains the required child proofing and tightness.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International application PCT/DK2004/000032 filed Jan. 21, 2004, the entire content of which is expressly incorporated herein by reference thereto.

BACKGROUND

The invention relates to a locking arrangement for detachably locking a cap with a skirt on a container with an enclosure opening into an opening, and of the kind that comprises a number of keys spaced along the inside of the skirt of the cap; a number of projections spaced along the outside of the enclosure of the container in an area having a mainly circular cross section and defining an axis; a slot made in each projection and having a base at the opening of the container and an opposite inlet for insertion of a key; and cooperative contact faces made on the skirt and enclosure respectively and forming an angle with each other seen in cross section.

Detachable caps are especially used for containers having a content which is not to be used at one time. Therefore, the cap must be able to be mounted and demounted repeatedly. For this purpose threaded joints are typically used that in some cases only are fragmentary to thereby be able to screw a cap off and on quicker and more easily.

The content in a container can be dangerous. Such containers must therefore be protected against the cap being demounted by children that could get hurt by thereby coming into contact with or eating some of the dangerous content.

A solution which is much used for bottles and containers having a dangerous content is to use a threaded joint with the internal thread located on a separate insert in the cap in an arrangement which conditions that the cap is pressed in towards the bottle. Thereby the insert is coupled to the cap and is therefore brought along when the cap is rotated so that it now can be screwed off.

From U.S. Pat. No. 5,449,078 is known a container made of an elastic material and comprising a detachable cap with a skirt for closing an opening in an enclosure on the container. On the inside of the skirt of the cap are a number of keys for engaging slots in a number of projections on the outside of the enclosure of the container in mounted state. A sealing ring in the cap cooperates with a taper on the enclosure of the container at mounting and demounting of the cap.

In mounted state in which the keys are in their slots, the sealing ring is kept in an elastically expanded state by the taper. Tensile stresses are therefore created in the sealing ring that, due to the angle the ring forms with the taper, will affect the cap with an axial spring power that keeps the keys in the slots. Therefore it is only possible to remove the cap by pressing it in towards the container while overcoming said spring power until the keys are free of the slots so that the cap now can be rotated free of the projections and finally be removed from the container.

This operation is difficult for children. The known container is therefore child-proof, i.e. a child cannot remove the cap and thereby get possession of e.g. a dangerous medical preparation that could cause damage to the child.

In many respects, the arrangement constitutes an excellent child proofing for a container which is closed by a cap. When the cap, which normally is made of plastic, is mounted on the container, its sealing ring is however loaded by considerable tensile stresses that cause the plastic to be permanently deformed so that the arrangement in the end no longer is sufficiently child-proof or sufficiently tight.

This problem is especially serious if the sealing ring of the cap unintentionally has been left in a position in which it is loaded more by tensile stresses than in the final closed position. In this case the plastic is quickly deformed, whereby the child proofing and tightness of the arrangement are cancelled with a corresponding fastness.

A second problem is that it is the abutment of the sealing ring against the taper that establishes the necessary tightness. To be able to obtain sufficiently great axial spring force to make the arrangement child-proof, the sealing surfaces on the sealing ring and taper respectively are exposed to rather great surface pressure that wears the sealing surfaces and thereby eliminates the required tightness.

A third problem is that the arrangement is difficult to operate. The reason for this is especially that the cap during mounting and demounting has to be rotated while overcoming the great friction existing between the sealing surfaces.

Thus, the present invention has been made to address these problems and provide an improved locking arrangement.

SUMMARY OF THE INVENTION

The invention now provides a locking arrangement of the kind mentioned in the opening paragraph, which is easy to operate and continuously maintain the required child proofing and tightness.

According to the invention, this arrangement is obtained by the contact faces of the cap being made on the inside of the skirt and/or the free ends of the keys and by the contact faces of the container being made on the projections and/or enclosure at a greater distance from the axis than the contact faces of the cap.

The design requires that the cap and container and thereby their respective contact faces are pressed against each other to thereby allow the keys to be rotated in under the inlet of the slots when the cap is rotated in relation to the container. As the contact faces form an angle with each other, the skirt and enclosure are deformed elastically during this, whereby they are loaded by stresses of a component of force that acts on the cap and container in each their direction.

The skirt of the cap and the enclosure of the container are however only loaded by weaker bending stresses as they are bent instead of, as the sealing ring from the cap known from U.S. Pat. No. 5,449,078, being stretched and thereby loaded by great tensile stresses with subsequent considerable problems to the use and functioning of the arrangement.

Even if the locking arrangement according to the invention has been in a locked state for a relatively long period in total, the elastic deformation of the skirt and enclosure will therefore be relatively small. Thereby the considerable advantage is obtained in that the cap and container continuously maintain their original shapes and that the arrangement is enabled to continuously maintain the required child proofing and tightness.

Another advantage is that the friction between the contact faces is modest. Therefore great frictional forces do not have to be overcome between the contact faces when the cap is to be mounted and demounted and these operations are now therefore easy to perform.

The bending stresses will especially be small if at least a part of the skirt of the cap is wave-shaped with a wave crest at each key and a wave hollow in the gap between each of two adjacent keys. This is due to the fact that the skirt thereby is given a shape that can easily be bent.

By fitting a separate sealing ring in the cap for sealing against the inside of the enclosure of the cap, it is furthermore advantageously obtained that the tightness in the locked state will be independent of the engagements between the contact faces.

The slot in each projection can expediently be defined by a first rib extending along the base of the slot, and second and third ribs extending along the sides of the slot whereby the second rib can extend past the inlet of the slot and the third rib can have a lateral edge extending from the opening of the slot in a direction obliquely towards the opening of the container.

The oblique lateral edge on the third rib forces the keys of the cap, upon rotation of the cap in relation to the container, in under the inlet of the slot, after which they can be guided to locked state in the slots. During this, the longer second rib prevents the keys from rotating past the inlets.

Where the contact faces of the cap and the enclosure mutually form an angle which is not self-locking, the advantage is obtained in that the keys are automatically pushed into the slots whereby a safe mounting of the cap is obtained.

According to the invention, the distance from the axis to the contact faces of the container can decrease in the direction towards the base of the slot to correspond to or be shorter than the distance from the axis to the contact faces of the cap in the detached state of the cap whereby mounting and demounting of the cap is facilitated.

Where the enclosure of the cap is defined by an edge extending past the areas on the projections where the distance between the contact faces of the container and the axis is the shortest in the locked state of the locking arrangement, it is obtained that the cap will be firmly fixed on the container.

In this case, the skirt and the enclosure are at least to some extent loaded by stresses. In a second embodiment the edge of the enclosure can merely extend to or near the areas on the projections where the contact faces of the container is the shortest from the axis, In this case, the skirt and enclosure are not or hardly loaded by stresses whereby the risk of the skirt and enclosure being permanently deformed is completely eliminated. This has the advantage of the cap and container being able to continuously maintain their shape for certain.

Where the contact faces of the cap have mainly the same configuration as the opposite contact faces of the container in the locked state of the locking arrangement, it is advantageously obtained that the load on the contact faces is distributed over an adequate area instead of being concentrated in points or lines. Thereby the wear that said faces are subjected to when the cap is repeatedly mounted and demounted is reduced.

Where the contact faces of the container are made on the projections, the radius of curvature in a cross section through these contact faces can correspond to or be smaller than the radius of curvature in a cross section through the opposite contact faces of the cap in the locked state of the locking arrangement. Thereby it is for certain avoided that the projections are completely or partly loaded via their lateral edges, by which the contact faces of the cap could be worn and exposed to tears.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in greater details below, describing only exemplary embodiments with reference to the drawing, in which:

FIG. 1 is a perspective view obliquely from below of a container and cap according to the invention in a state in which the cap is removed,

FIG. 2 is a side elevational view of the container in FIG. 1 with the cap in a first mounting step on the container and a part of the skirt of the cap removed,

FIG. 3 is the view in FIG. 2 in a subsequent mounting step,

FIG. 4 is the view in FIG. 2 in the locked position of the cap on the container,

FIG. 5 is a perspective view obliquely from above of a second embodiment of the container according to the invention,

FIG. 6 is a sectional view of a second embodiment of the cap according to the invention with wave-shaped skirt.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-4 show a container 1 with a detachable cap 2. In this case it is assumed that both parts are made of plastic.

The container and the cap are in the case shown circular and define an axis shown in dash-dot line. The container has a base 3 and an enclosure 4 with an opening 5. The cap has a base 6 and a skirt 7 with a free edge 8.

In FIG. 1 the cap is shown in detached state whereas it is shown during mounting in FIGS. 2-4. In FIGS. 2-4 an imaginary window has been cut out in the enclosure of the cap allowing viewing of the mounting operation.

At the opening in the enclosure of the container six projections 9 are made in this case evenly spaced along the outside of the enclosure. In each projection a slot 10 is made with a base 11 near the opening of the enclosure and an inlet 12 facing in opposite direction. As shown, the inlet can have a rectangular configuration but can also taper in the direction from the opening of the slot to its base, for example along a first section emanating from the opening of the slot and continuing in a second section with rectangular configuration.

A first rib 13 is extending along the base of the slot whereas second-and third ribs 14 and 15 are extending along each their side of the slot. The second rib is extending a distance past the opening of the slot and is made with an outside 16 extending obliquely inclined from the free end of the rib in direction towards the base of the slot. The third rib has a lateral edge 17 extending obliquely outwards from the opening of the slot in direction towards the opening of the container.

In the case shown, this edge is arc-shaped with a tangent forming an increasing angle with the adjacent side in the slot in the direction from the opening of the container to the opening of the slot. Alternatively, the lateral edge can be straight.

On the inside of the enclosure of the cap six keys 18 are made fitting in each their slot. The inside of the skirt is furthermore at a shorter distance from the axis than the oblique outside of the second rib. A sealing ring 19 located on the inside of the base of the cap is extending towards the base of the cap at a distance from its skirt.

At mounting of the cap 2 this cap is first guided down over the container 1 with the keys 18 in the gaps between the projections 9. This is allowed as each key has a width corresponding to or slightly smaller than the distance between two adjacent projections.

Then the cap is rotated in relation to the container and clockwise in the case shown as indicated by the arrow.

FIG. 2 shows the beginning of this operation. The keys are now engaging the part of the arc-shaped lateral edge 17 nearest the opening 5 of the container on each of the third ribs 15.

As shown in FIG. 3, the engagement between the keys and the lateral edges of the third ribs effects the cap to be screwed a distance onto the container in the oblique direction indicated by the arrow during the continued rotation.

In FIG. 4 the keys are rotated free of the lateral edge of the third ribs, after which the keys of the cap have been guided into each their slot via the opening 12 of this slot by axially displacing the cap in the opposite direction of the container as shown by the arrow. The longer second rib 14 functions as stop to the keys in this connection and thereby against further rotation of the cap. Thereby it is effectively ensured that the keys are always guided securely into their respective slots during mounting of the cap onto the container.

The locking arrangement is now in the locked state, in which the sealing ring in the cap is abutting on the inside of the enclosure of the cap in a sealing manner.

As mentioned above, the inside of the enclosure of the cap is at a shorter distance from the axis than the oblique outside 16 on the second rib of the projections. This means that the skirt 7 of the cap and the enclosure 4 of the container necessarily have to be deformed to be able to allow the cap to be mounted on the container as described above.

The skirt and enclosure are elastically deformed whereby the two parts are loaded by internal stresses with a component of force that tries to press the cap and the container in opposite directions whereby the keys are automatically pushed into the slots in the state in FIG. 4 when the oblique outside of the second rib of the projections form a not self-locking angle with the axis. The stresses are mainly generated by bending of the skirt and enclosure and therefore only reach a value which the plastic can withstand for a very long time without thereby being inflicted with significant permanent deformations. Thereby the considerable advantage is obtained in that both the cap and the container maintain the shape they each had from the beginning.

Demounting of the cap takes place by performing the operations performed to mount the cap in reverse order. But this requires that the cap is first pressed in towards the container while overcoming the above component of force to thereby take the keys out of their slots and allow the cap to be rotated anticlockwise.

This operation is too difficult to perform for a child. The locking arrangement according to the invention is therefore child-proof.

FIG. 5 shows a second embodiment of a locking arrangement according to the invention. This embodiment corresponds to the embodiment described above with reference to FIGS. 1-4. The same reference numerals are therefore used for like parts.

In this case the end faces 20 of the keys 18 are cooperating with an oblique face 21 made on the container 22 and located at a greater distance from the axis than said end faces. This locking arrangement moreover functions in the same way as the first locking arrangement and the same advantages are also obtained, and this embodiment will therefore not be described in detail here.

It is to be noted that the two locking arrangements can be used separately but also together.

FIG. 6 shows a second embodiment of a cap 23 according to the invention with a wave-shaped skirt 24 that readily can be deformed without generating great internal stresses.

The invention is described above and shown in the drawing on basis of only exemplary embodiments. Within the scope of the invention many other embodiments are however possible.

Thus the oblique outside on the second rib does not have to be defined by this rib but can be made on the entire projection or parts of this projection (not shown).

The skirt of the cap or only the inside of this skirt can furthermore be conic (not shown) whereas the second rib merely can be made with a boss at the end (not shown).

The number of projections need not be six either but can for example be less, for example three. Thereby the advantage is obtained in that the cap is inclined to overturn when it is to be demounted so that one or two of the keys do not get completely free of their slots. In this case the cap can therefore not be demounted.

Therefore it is necessary that the cap is pressed down towards the container without overturning at least significantly. But this requires relatively great attention on the user side, which children lack. By a few projections an additional child proofing is therefore obtained by means of the locking arrangement according to the invention, that forms a child proofing together with the child proofing described above which is safer than hitherto known.

The arrangement according to the invention is suited for containers which are used for pills and tablets. 

1. A locking arrangement for detachably locking a cap onto a container opening, which comprises: a container that includes an enclosure associated with an opening and a number of projections spaced along the enclosure exterior in an area having a substantially circular cross section, with each projection having a slot and base, defining an axis, and having an opposite inlet for insertion of a key; and a cap for closing the enclosure and container opening and having a skirt that includes a number of keys spaced along its interior for engaging the enclosure projections; wherein the cap and enclosure projections have cooperative contact faces that form an angle with each other when viewed in axial cross section, and the contact faces of the container are spaced at a greater distance from the axis than the contact faces of the cap.
 2. The locking arrangement of claim 1, wherein the contact faces of the cap are located on the inside of the skirt.
 3. The locking arrangement of claim 1, wherein the keys have free ends and the contact faces of the cap are located on the free ends of the keys.
 4. The locking arrangement of claim 1, wherein the contact faces of the container are located on the projections.
 5. The locking arrangement of claim 1, wherein the contact faces of the container are located on the enclosure.
 6. The locking arrangement of claim 1, wherein the distance from the axis to the contact faces of the container decreases in a direction towards the base of the slot to a distance that corresponds to or is shorter than the distance from the axis to the contact faces of the cap in the demounted state of the cap.
 7. The locking arrangement of claim 6, wherein the skirt of the cap is defined by an edge extending past the areas on the projections where the distance between the contact faces of the container and the axis is the shortest in the locked state of the locking arrangement.
 8. The locking arrangement of claim 6, wherein the skirt of the cap is defined by an edge extending to or near the areas of the projections where the distance between the contact faces of the container and the axis is the shortest in the locked state of the locking arrangement.
 9. The locking arrangement of claim 1, wherein the contact faces on the cap and enclosure respectively do not form a self-locking angle with each other.
 10. The locking arrangement of claim 1, wherein the contact faces of the cap have mainly the same configuration as the opposite contact faces of the container in the locked state of the locking arrangement.
 11. The locking arrangement of claim 1, wherein the contact faces of the container are made on the projections, and have a radius of curvature in cross section that corresponds to or is smaller than that of the opposite contact faces of the cap in the locked state of the locking arrangement.
 12. The locking arrangement of claim 6, wherein the slot in each projection is defined by a first rib extending along the base of the slot, and second and third ribs extending along the sides of the slot, with the second rib extending a distance past the inlet of the slot, and the third rib having a lateral edge extending obliquely outwards from the opening of the slot in direction towards the opening of the container.
 13. The locking arrangement of claim 1, wherein a sealing ring is fitted on a base of the cap, with the ring abutting closely on the inside of the enclosure of the container in the locked state of the locking arrangement.
 14. The locking arrangement of claim 1, wherein at least a part of the skirt of the cap is wave-shaped with a wave crest at each key and a wave hollow in the gap between each of two adjacent keys. 